This invention relates to the field of magnetic apparatus, especially as such apparatus is employed to generate relatively long uniform magnetic fields for devices such as an electrical signal delay line.
In the parent application, a large number of closely-spaced magnetomotive force generating elements 214, 216, 218, 220, 224 and 227 (i.e., the elements 214-227) in FIG. 2 of the parent application, are dispersed orthogonally along a magnetic path between two primary sources of magnetomotive force 205 and 206; the primary sources are located at opposite ends of a cavity 202. In this arrangement, the magnetic field developed by the orthogonal magnetomotive force generating elements 214-227 along the primary magnetic flux path is graduated in strength as required to achieve laminar magnetic flux within the cavity 202 by changing the relative magnetic strength of individual orthogonal magnetomotive force generating elements. This graduation in magnetic strength is indicated by the length of the arrows 256, 258, 259, 266, and 268 in FIG. 2 with the stronger dispersed field elements being located in the regions of greatest curvature of the primary magnetic flux lines adjacent the primary sources 205 and 206.
The required variations in the magnetic field produced by the dispersed orthogonal magnetic elements 214-227 in the parent application are achieved with some difficulty, especially in an experimental or small quantity environment. The achievement of magnets of graduated magnetization for use in the dispersed orthogonal magnetomotive flux generating locations of FIG. 2 in the parent application requires precision manufacturing techniques or other arrangements which are difficult to accomplish in laboratory and small quantity environments. The present invention provides a convenient, readily achieved answer for this difficulty and allows the use of simple, low-cost uniform magnetomotive force sources--in comparison with those used in the above-identified parent application apparatus.
The following patents are believed to have some relevance to the present application: U.S. Pat. Nos. 3,480,888; 3,530,409; 3,593,215; 3,895,324; 3,946,340; 4,093,929; 4,152,676; 4,152,677; 3,383,632; 4,165,498; 3,309,628; 3,290,649; 3,707,689; 3,244,993; 2,814,793; 3,225,312; 3,444,484; 4,114,532; 2,983,840; 3,199,513; 2,722,617; 3,257,141; and 3,206,655. All except the latter six of these prior patents were considered during prosecution of the parent application.